Fluid filter device

ABSTRACT

A housing has a closed end and a closure plate at its other end, the plate being provided with a fluid inlet and a fluid outlet. A filter cartridge is positioned in the housing against a support on the closure plate, the cartridge including a central tubular discharge member which communicates with the fluid outlet. A leaf spring adapter is interposed between the other end of the cartridge and the closed end of the housing to bias the cartridge against the support on the plate. The adapter has a central opening which is normally covered by a spring-pressed valve element, but the valve element is deflectable from the adapter to uncover the opening by excessive fluid pressure differential between the outside of the cartridge and the inside of the discharge member. In some embodiments the valve element is imperforate and normally closes the opening in the adapter, becoming open when flow through the cartridge is blocked. In another embodiment the valve element has an opening in register with that in the adapter and the opening in the valve element is covered by a screen which constitutes a secondary filtering medium additional to the primary filtering medium afforded by the cartridge. In that embodiment the valve element becomes open when the screen is blocked, as it does in still other embodiments where the valve element may be the screen itself.

United States Patent [191 Shaltis et a1. 1

m1 3,822,787 July 9,1974

[ FLUID FILTER DEVICE [75] Inventors: Robert J. Shaltis; David Woltjer,

both of Hastings, Mich.

[73] Assignee: Hastings Manufacturing Company,

Hastings, Mich.

22 Filed: May 8, 1972 21 Appl. No.: 250,925

Related US. Application Data [63] Continuation-in-part of Ser. No.206,713, Dec. 10,

1971, Pat. No. 3,722,683.

Primary Examiner-Frank A. Spear, Jr.

[57] ABSTRACT A housing has a closed end and a closure plate at itsother end, the plate being provided with a fluid inlet and a fluidoutlet. A filter cartridge is positioned in the housing against asupport on the closure plate, the cartridge including 'a central tubulardischarge member which communicates with the fluid outlet. A leaf springadapter is interposed between the other end of the cartridge and theclosed end of the housing to bias the cartridge against the support onthe plate. The adapter has a central opening which is normally coveredby a spring-pressed valve element, but the valve element is deflectablefrom the adapter to uncover the opening by excessive fluid pressuredifferential between the outside of the cartridge and the inside of thedischarge member. In some embodiments the valve element is imperforateand normally closes the opening in the adapter, becoming open when flowthrough the cartridge is blocked. In another embodiment the valveelement has an opening in register with that in the adapter and theopening in'the valve element is covered by a screen which constitutes asecondary filtering medium additional to the primary filtering mediumafforded by the cartridge. in that embodiment the valve element becomesopen when the screen is blocked, as it does in still other embodimentswhere the valve element may be the screen itself.

24 Claims, 12 Drawing Figures PATENTED JUL 91974 SHEET 1 BF 3 FIG].

as so 29 28 @(MDQOQGJG) PAIENTEnm sum SHEET 2 0F 3 PATENTED 91974 SHEET3 0F 3 FIG. /0.

F/ a. ll.

If vi FLUID FILTER DEVICE RELATED APPLICATIONS This invention relates tonew and useful improvements in fluid filter devices, and in particularthe invention concerns itself with so-called spin-on type of filtersused in the lubricating systems of internal combustion engines or thelike.

' A filter of this general type hasa housing containing a filtercartridge, the housing including a closure plate at one end thereofwhich is provided with an-oil inlet and an oil outlet. The oil flowsinto the housing to the outside of the cartridge, then inwardly throughthe filt er material of the cartridge and into a central tubulardischarge member of the cartridge, from where it leaves through the oiloutlet in the closure plate. Usu- I ally, a spring is interposed betweenthe cartridge and the other, closed end of the housing to bias thecartridge into engagement with the closure plate, or a gasket or someother support means provided on the closure plate.

It is customary in the art to provide some type of a pressure reliefvalve or a by-pass valve so that oil may flow from the outside of thecartridge directly into the discharge member when flow through thefilter material of the cartridge is impeded or blocked. It is also.known, as in the two aforementioned applications Ser. No. 36,971 and,113,283 to provide a dual flow arrangement with a primary fluid flowthrough the cartridge and a secondary fluid flow through a screen at ametered rate, so as to accommodate full flow requirements of aparticular lubricating system. The aforementioned applications alsoprovide for a by-pass for the secondary filter screen under excessivefluid pressure, as when flow through the screen becomes impeded orblocked.

The present invention has as its principal object to provide an improvedfluid filter device in which a leaf spring type of an adapter isprovided at the closed end of the housing to bias the cartridge towardthe closure plate at the other end, in place of a helical compressionspring which is commonly used for that purpose.

In conjunction with the leaf spring adapter, another object of theinvention is to provide a spring-pressed valve element which cooperateswith an opening at the center of the adapter for by-passing fluid intothe tubular discharge member of the cartridge when flow through thefiltermaterial of the cartridge is blocked.

in modified embodiments, another object of the invention is to utilize afilter screen as the valve element in a dual flow arrangement of thefilter, the screen being spring-pressed and also functioning as aby-pass valve when flow through the screen is blocked.

With the foregoing more important objects and features in view and suchother objects and features which may become apparent as thisspecification proceeds, the invention will be understood from thefollowing description taken in conjunction with the accompanyingdrawings, wherein like characters of reference designate like parts, andwherein:

FIG. 1 is a vertical sectional view of a fluid filter device embodyingthe invention;

FIG. 2 is an enlarged, fragmentary sectional view of the upper endportion of the cartridge, also showing the adapter, valve element andscreen;

FIG. 3 is a plan view of the adapter per se;

FIG. 4 is a sectional view taken substantially in the plane of the line44 in FIG. 3;

FIG. 5 is a plan view of the valve element and screen thereon;

FIG. 6 is a fragmentary vertical sectional view showing a modifiedembodiment of the invention;

FIG. 7 is a plan view of the valve element, taken substantially in theplane of the line 7-.-7 in FIG. 6',

FIG. 8 is a view similar to FIG. 6 but with the valve element in theopen position;

FIG. 9 is a vertical sectional view showing another modified embodimentof the fluid filter device;

FIG. 10 is an enlarged, fragmentary sectional view of the upper endportion of the device shown in FIG. 9;

FIG. 11 is a fragmentary sectional view of another modified embodiment;and

FIG. 12 is a fragmentary sectional view of still another modifiedembodiment.

Referring now to the accompanying drawings in detail, the fluid filterdevice of the invention shown in FIG. 1 is designated by the generalreference numeral 10 and is inthe form of a spin-on type oil filter usedin lubricating systems of internal combustion engines, or

the like.

The filter 10 includes a housing 11 with a closed end 12 and an open endwhich is closed by a closure plate 13 in the conventional manner, theclosure plate having a central fluid outlet 14 and a plurality of fluidinlets 15 arranged in circular formation around the outlet. The outletis internally screw-threaded for mounting the entire filter on theengine block. A filter cartridge 16 is positioned in the housing 11 andincludes a central tubular discharge member 17 surrounded by filteringmaterial 18, the outer wall 19 of the cartridge and the central member17 being perforate so that oil entering the housing through the inlets15 may flow to the outside of the cartridge and then inwardly throughthe filter material 18 into the central discharge member 17 in theconventional manner. The lower end of the cartridge 16 is seated on asuitable support which in the illustrated instance is represented by agasket 20 of rubber, or the like. The gasket surrounds the oil outlet 14and the engagement of the lower end portion 21 of the cartridge with thegasket isolates the outlet 14 from the inlets 15 so that oil in thecentral member 17 of the cartridge flows out through the outlet 14. Inthe illustrated instance the gasket 20 also serves as a valve whichcloses the inlets l5 and prevents drain-back therea one piece leafspring adapter 22 which is interposed between the upper end of thecartridge and the closed end 12 of the housing 11. As shown in the planview of FIG. 3, the leaf spring adapter 22 is substantially rectangularand has arcuate end portions 23 which seat against the inside of theclosed end 12 of the housing. Intermediate portions 24 of the adapterslant downwardly and inwardly toward a depressed or well-shaped centerportion 25 and the latter is tightly fitted into an annular recess 26provided in the upper end portion of the cartridge 16, concentricallywith the central discharge member 17, as will be apparent from FIG. 1.The recess 26 has a circumferential wall 27 and an annular shoulder 28,the center portion 25 of the adapter being telescoped in the wall 27.The axial depth of the recess 26 is greater than that of the depressedcenter portion 25 of the adapter, so that the center portion 25 isspaced upwardly from the shoulder 28, as will be understood from FIGS. 1and 2.

The center portion 25 of the adapter 22 is provided with a centralopening 29 which communicates with the interior of the discharge member17 of the car tridge 16. The filter shown in FIGS. 1 and 2 is a dualflow filter of the type disclosed in the aforementioned applicationsSer. No. 36,97l and No. 113,283. In this type of filter a primary fluidflow is provided through the filter material 18 of the cartridge 16, anda secondary fluid flow is provided through a screen directly into thetubular discharge member 17 through a metering orifice. The screen is acoarser filtering medium than the filter material of the cartridge andis provided to accomodate the quantity of oil pumped through thelubricating system which is in excess of the amount of oil capable ofbeing handled by the finer filtering material of the cartridge.

In a dual flow filter of this type, the secondary oil flow is throughthe opening 29 of the adapter 22 into the discharge member 17 of thecartridge, the opening 29 being of such size as to serve as a meteringorifice for the secondary flow. The filter screen 30, substantiallycircular in shape as shown in FIG. 5, is supported below the centerportion 25 of the adapter by a leaf spring type valve element 31 whichis disposed in the recess 26 and seated on the annular shoulder 28. Thevalve element 31 as shown in FIG. has a circular center portion 32integral with a plurality of resiliently flexible legs 33 which radiatefrom the center portion and seat on the shoulder 28, as will be apparentfrom FIG. 2. The center portion 32 is formed with an opening 34 of thesame size as the opening 29 in the adapter 22. The screen 30 ispositioned on top of the center portion 32 of the valve element 31 andthe periphery of the screen is provided integrally with a set ofdownturned tabs 35 which are received in spaces between the legs 33 ofthe valve element, thus retaining the screen in concentric position onthe valve element. The resiliency of the valve element 31 normallybiases the screen 30 against the underside of the center portion 25 ofthe adapter 22.

In operation, primary oil flow is through the filter material 18 of thecartridge 16 into the discharge member 17. Secondary oil flow is throughthe metering opening 29 in the adapter 22, through the screen 30, andthrough the opening 34 in the valve element 31 into the discharge member17. If either or both the primary oil flow and the secondary oil flowshould become impeded or blocked, the fluid pressure at the outside ofthe cartridge 16 will rise abnormally above that inside the dischargemember 17 and the excessive pressure differential will cause the screen30 and the center portion 32 of the valve element 31 to be deflecteddownwardly or away from the underside of the center portion 25 of theadapter 22. Thus the oil will by-pass the screen 30 and will flowdirectly into the discharge member 17.

FIG. 6-8 illustrate a modified embodiment of the invention in a singleflow type filter which does not have a secondary flow through a screensuch as the screen 30 in the embodiment of FIGS. 1-5. The structure inFIGS. 6-8 is similar to that already described, except that the screen30 is omitted and the center portion 32a of the valve element 31a is notprovided with the opening 34, and a corrugated paper cartridge 118 issubstituted for the depth cartridge 18 shown in the earlier embodiments.

The resilient valve element 31a is biased so that its center portion 32anormally closes the opening 29 in the adapter 22, as long as there issatisfactory flow through the filter material of the cartridge 16.However, if that flow is impeded or blocked, the excessive pressuredifferential causes the center portion 32a of the valve element to bedeflected downwardly from the center portion 25 of the adapter 22 asshown in FIG.. 8, permitting oil to flow directly into the dischargemember 17 of the cartridge in by-pass of the cartridge filteringmaterial. The closed position of the valve element 31a is illustrated inFIG. 6.

FIGS. 9 and 10 illustrate another modified embodiment of the valvearrangement in a filter of the type shown in FIG. 1, and since thefilter structure is the same, corresponding reference numerals are usedin FIG. 9 and 10. However, in this instance the central tubulardischarge member 117 is co-extensive with the length of the cartridge16,-extending between the end caps 40 and 41 of the cartridge and beingsecured to end caps as at 42 (see FIG. 10).

The leaf spring adapter 22 includes a wide flat portion 22a whichengages the flat end cap 40 and the center portion 25 of the adapter istightly fitted into the adjacent end portion of the tubular member 117,the portion 25 being provided with the opening 29 which com municateswith the interior of the discharge member 117, as will be apparent. Aninwardly projecting annular shoulder 43 is formed integrallyintermediate the ends of the tubular member 117, adjacent the end cap 40for seating a helical compression spring 44. The annular shoulder 43 isa flattened annular bead formed by inwardly beading the tubular member117 and then flattening the bead out so that the surface of bead onwhich the coil spring 44 rests lies in a plane which is substantiallyperpendicular to the longitudinal axis of the'tubular member 117. Thespring bears against a valve element 45 and urges it against the centerportion 25 of the adapter 22 so that the valve element normally coversthe opening 29. If the filter is a dual flow filter with a primary flowthrough the filtering medium 18, the valve element comprises a screendisc and the secondary flow takes place through it, directly into thedischarge member 117. The opening 29 is of such size as to serve as ametering orifice for the secondary flow. The screen 45 is a coarserfiltering medium than the filter medium 18 of the cartridge, and thesecondary flow through the screen is provided to accomodate the quantityof oil pumped through the lubricating system in excess of the amount ofoil capable of being handled by the finer material of the filteringmedium 18 in the primary flow.

If either or both the primary flow through the filter medium 18 and thesecondary flow through the screen 45 should become blocked or impeded,the fluid pressure at the outside of the cartridge 16 will riseabnormally above that inside the discharge member 117 and the excessivepressure differential will cause the screen 45 to be deflected away fromthe center portion 25 of the adapter 22, against the action of thespring 44. The opening 29 will thus be uncovered and the oil will flowthrough the opening directly into the discharge memher 117.

Of course, if the filter should be a single flow type, with flownormally through the filter medium 18 of the cartridge, the valveelement 45 may be a solid, imperforate disc which normally closes theopening 29 and blocks oil flow therethrough. However, if flow throughthe filter medium 18 is blocked or impeded, the abnormally high fluidpressure at the outside of the cartridge will deflect the valve elementfrom the adapter portion 25 to uncover the opening 29 and by-pass theflow directly into the discharge member 117.

F I6. 11 shows another modified embodiment which is somewhat similar tothat in FIGS. 6-8 insofar that it utilizes a corrugated paper cartridge118 with a single fluid flow therethrough. The cartridge is providedwith an end cap 50 which is engaged by the leaf spring adapter 22. Theend cap 50 is annular and is formed integrally at the center thereofwith an inwardly projecting circumferential wall 51 which terminates atits inner end in an inturned annular shoulder 52.

The annular wall 51 is disposed concentrically within the centraldischarge passage 118a of the cartridge 118, and the central portion 25of the adapter 22 is fitted tightly into the annular wall 51 at the endcap 50. The wall 51 contains a helical compression spring 44 which isseated on the shoulder 52 and urges a valve element 45 against theadapter portion 25 so as to cover the opening 29.

In the instance of a single flow filter with a paper cartridge such asthe cartridge 118, the valve element45 comprises a solid, imperforatedisc which normally closes the opening '29 and becomes unseated againstthe action of the spring 44 in the event of abnormal pressure, tofacilitate oil by-pass directly into the discharge passage 118a.However, in a dual flow arrangement, the valve element 45 may be ascreen, facilitating secondary flow therethrough.

As already noted, the end cap 50, the circumferential wall 51 and theshoulder 52 in the embodiment of'FlG. 11 are integrally formed. FIG. 12illustrates a modified arrangement wherein the shoulder 152 is formedintegrally with the circumferential wall 151, but the latter is separatefrom the end cap 150. In this instance the wall 151 is provided at itsouter end with an outtumed annular flange 153 which is interposedbetween the end cap 150 and the leaf spring adapter 22, thus holding theparts assembled. Otherwise, the arrangement of the spring 44 and valveelement 45 in FIG. 12 is the same as already described in connectionwith FIG. 11.

As will be apparent the invention is generally applicable to variousdepth type cartridge constructions as well as to paper cartridgeconstructions as will be apparent to those skilled in the art, the depthtype filter material being well known in the art as is also the papertype cartridge construction.

While in the foregoing there have been described and shown the preferredembodiments of the invention, various modifications may be resorted towithin the spirit and scope of the invention as claimed.

What is claimed is:

1. In a fluid filter device, the combination of a housing having aclosed end and an open end, a closure plate closing the open end of thehousing and provided with a fluid inlet and fluid outlet, a filtercartridge posi tioned in the housing and including a central tubulardischarge member communicating with said fluid outlet, support means onsaid closure plate for the adjacent end of said cartridge, one-pieceleaf spring adapter interposed between the other end of the cartridgeand said closed end of the housing for biasing the cartridge againstsaid support means, said adapter having a central opening communicatingwith said tubular discharge member, a spring-pressed valve elementinterposed between said other end of the cartridge and said adapter,said valve element normally covering said opening in the adapter butbeing deflectable from the adapter to uncover the opening as a functionof excessive fluid pressure differential at the outside of the cartridgeand the inside of said discharge member, and coil-spring means urgingsaid valve element against said adapter to close said opening.

2. The device as defined in claim 1 which is further characterized inthat said valve element is imperforate and normally closes said openingin the adapter.

3. The device as defined in claim 1 wherein said valve element isprovided with an opening in register with the opening in the adapter,and a screen positioned on the valve element and covering the openingtherein, said screen constituting a secondary filtering mediumadditional to a primary filtering medium afforded by said cartridge.

4. A device as defined in claim 1 wherein the filter cartridge includesa depth type filler.

5. A device as defined in claim 1 wherein the filter cartridge is of thepaper type.

6. In a fluid filter device, the combination of a housing having aclosed end and an open end, a closure plate closing the open end of thehousing and provided with a fluid inlet and a fluid outlet, a filtercartridge positioned in the housing and including an annular filtermedia having a central discharge opening extending longitudinallythrough the annular filter media and communicating with said fluidoutlet, support means on said closure plate for the adjacent end of saidcartridge, a one piece leaf spring adapter interposed between the otherend of said cartridge and said closed end of the housing for biasing thecartridge against said support means, said adapter having a centerportion closing said central discharge opening at one end and having abypass opening communicating with said central discharge opening andspaced resilient finger portions extending outwardly from said centerportion and bearing against the inner surface of said closed end of saidhousing, said filter cartridge having an annular shoulder within saidcentral discharge opening which is spaced inwardly from said other endof said cartridge and from said adapter, 21 valve element interposedbetween said annular shoulder and said adapter and normally coveringsaid bypass opening, resilient means interposed between said annularshoulder and said valve element for biasing said valve element againstsaid adapter, said resilient means comprising compressible coil springmeans deflectable from said adapter to permit said valve element touncover said central opening in said adapter as a function of excessivefluid pressure differential at the outside of the cartridge and theinside of said central discharge.

7. The device set forth in claim 6 wherein said filter cartridge furtherincludes an annular end cap covering said annular filter media at saidother end thereof and a circumferential wall extending inwardly intosaid central discharge opening from said end cap at one end andterminating in said annular shoulder at its inner end.

8. The device as set forth in claim 7 wherein said circumferential wallis integrally joined to said annular end cap and to said annularshoulder.

9. The device as set forth in claim 7 wherein said end cap,circumferential wall and annular shoulder are of one piece construction.

10. The device as set forth in claim 9 wherein said filter media is apaper filter and said valve element is imperforate and normally closessaid opening in said adapter.

11. The device as set forth in claim 7 together with a tubular dischargemember joined to the inner circumference of said annular shoulder andextending through said annular filter media to the adjacent end of saidcartridge.

12. The device as set forth in claim 11 wherein said filter media is adepth type filter and said valve element is a secondary filter media.

13. The device set forth in claim 6 wherein the center portion of saidleaf spring adapter is formed with a cylindrical wall extending axiallyinwardly into said central discharge opening and a transverse bottomwall at the inner end of said cylindrical wall through which said bypassopening extends.

14. In a fluid filter device, the combination ofa housing having aclosed end and an open end, a closure plate closing the open end of thehousing and provided with a fluid inlet and a fluid outlet, a filtercartridge positioned in the housing and including an annular filtermedia having a central discharge passage extending longitudinallythrough the annular filter media and communicating with said fluidoutlet, support means on said closure plate for the adjacent end of saidcartridge, a one piece leaf spring adapter interposed between the otherend of the cartridge and said closed end of the housing for biasing thecartridge against said support means, said adapter having a centralopening communicating with said discharge passage in said filter media,said cartridge also including an annular end cap covering said annularfilter media and engaged by said leaf spring adapter, an innercircumferential wall extending inwardly from said end cap concentricallywith said discharge passage, and an annular shoulder on saidcircumferential wall in inwardly spaced relation from said end cap,together with a compression spring within said circumferential wallseated on said annular shoulder, and a valve element interposed betweensaid spring and said adapter, said valve element normally covering saidopening in the adapter but being deflectable from the adapter againstthe action of said spring to uncover the opening as a function ofexcessive fluid pressure differential at the outside of the cartridgeand the inside of said discharge passage.

15. The device as set forth in claim 14 which is further characterizedin that said valve element is imperforate and normally closes saidopening in the adapter.

16. The device as set forth in claim 14 which is further characterizedin that said valve element comprises a screen covering said opening inthe adapter, said screen constituting a secondary filtering mediaadditional to the annular filter media of said cartridge.

17. The device as set forth in claim 14 wherein said adapter has asubstantially circular center portion provided with said opening, saidcenter portion of the adapter being seated within said innercircumferential wall of said cartridge.

18. The device as set forth in claim 14 wherein said innercircumferential wall of said cartridge is longitudinally coextensivewith said filter media and defines said discharge passage, said annularshoulder being provided intemiediate the ends of said circumferentialwall adjacent said end cap.

19. The device set forth in claim 18 wherein said annular shoulder is aflattened annular bead formed integrally with said inner circumferentialwall.

20. The device as set forth in claim 14 wherein said end cap and saidinner circumferential wall and said annular shoulder are of one-piececonstruction.

21. The device as set forth in claim 14 wherein said innercircumferential wall and said annular shoulder are of one-piececonstruction but separate from said end cap, said circumferential wallhaving an outer endprovided with an out-turned flange which isinterposed between the end cap and said adapter.

22. The device as set forth in claim 14 wherein a portion at least ofthe annular end cap is substantially flat and the leaf spring adapterincludes end portions engaging the interior of the closed end of thehousing and flat intermediate portions engaging the flat annular portionof said end cap over a substantial area.

23. In a fluid filter device, the combination of a housing having aclosed end and an open end, a closure plate closing the open end of thehousing and provided with a fluid inlet and a fluid outlet, a filtercartridge positioned in the housing and including an annular filtermedia having a central discharge opening extending longitudinallythrough the annular filter media and communicating with said fluidoutlet, support means on said closure plate for the adjacent end of saidcartridge, a spring adapter interposed between the other end of saidcartridge and said closed end of the housing for biasing the cartridgeagainst said support means, said adapter having a center portion closingsaid central discharge opening at one end and having a bypass openingcommunicating with said central discharge opening and resilient meansextending from said center portion and bearing against the inner surfaceof said closed end of said housing, said filter cartridge having firstimperforate tubular portion fitting snugly within said central dischargeopening and having an annular shoulder spaced inwardly from said otherend of said cartridge and from said adapter, said valve adapter alsoincluding a tubular portion fitting snugly within said first imperforatetubular portion and removable therefrom, a valve element comprising ascreen interposed between said annular shoulder and said adapter andnormally covering said bypass opening, and coil spring means interposedbetween said annular shoulder and said valve element for biasing saidvalve element against said adapter, said spring means being deflectablefrom said 10 wherein a perforated tubular discharge member extends fromsaid annular shoulder through said annular filter media to the end ofthe cartridge adjacent to the closure plate.

1. In a fluid filter device, the combination of a housing having aclosed end and an open end, a closure plate closing the open end of thehousing and provided with a fluid inlet and fluid outlet, a filtercartridge positioned in the housing and including a central tubulardischarge member communicating with said fluid outlet, support means onsaid closure plate for the adjacent end of said cartridge, one-pieceleaf spring adapter interposeD between the other end of the cartridgeand said closed end of the housing for biasing the cartridge againstsaid support means, said adapter having a central opening communicatingwith said tubular discharge member, a spring-pressed valve elementinterposed between said other end of the cartridge and said adapter,said valve element normally covering said opening in the adapter butbeing deflectable from the adapter to uncover the opening as a functionof excessive fluid pressure differential at the outside of the cartridgeand the inside of said discharge member, and coil-spring means urgingsaid valve element against said adapter to close said opening.
 2. Thedevice as defined in claim 1 which is further characterized in that saidvalve element is imperforate and normally closes said opening in theadapter.
 3. The device as defined in claim 1 wherein said valve elementis provided with an opening in register with the opening in the adapter,and a screen positioned on the valve element and covering the openingtherein, said screen constituting a secondary filtering mediumadditional to a primary filtering medium afforded by said cartridge. 4.A device as defined in claim 1 wherein the filter cartridge includes adepth type filler.
 5. A device as defined in claim 1 wherein the filtercartridge is of the paper type.
 6. In a fluid filter device, thecombination of a housing having a closed end and an open end, a closureplate closing the open end of the housing and provided with a fluidinlet and a fluid outlet, a filter cartridge positioned in the housingand including an annular filter media having a central discharge openingextending longitudinally through the annular filter media andcommunicating with said fluid outlet, support means on said closureplate for the adjacent end of said cartridge, a one piece leaf springadapter interposed between the other end of said cartridge and saidclosed end of the housing for biasing the cartridge against said supportmeans, said adapter having a center portion closing said centraldischarge opening at one end and having a bypass opening communicatingwith said central discharge opening and spaced resilient finger portionsextending outwardly from said center portion and bearing against theinner surface of said closed end of said housing, said filter cartridgehaving an annular shoulder within said central discharge opening whichis spaced inwardly from said other end of said cartridge and from saidadapter, a valve element interposed between said annular shoulder andsaid adapter and normally covering said bypass opening, resilient meansinterposed between said annular shoulder and said valve element forbiasing said valve element against said adapter, said resilient meanscomprising compressible coil spring means deflectable from said adapterto permit said valve element to uncover said central opening in saidadapter as a function of excessive fluid pressure differential at theoutside of the cartridge and the inside of said central discharge. 7.The device set forth in claim 6 wherein said filter cartridge furtherincludes an annular end cap covering said annular filter media at saidother end thereof and a circumferential wall extending inwardly intosaid central discharge opening from said end cap at one end andterminating in said annular shoulder at its inner end.
 8. The device asset forth in claim 7 wherein said circumferential wall is integrallyjoined to said annular end cap and to said annular shoulder.
 9. Thedevice as set forth in claim 7 wherein said end cap, circumferentialwall and annular shoulder are of one piece construction.
 10. The deviceas set forth in claim 9 wherein said filter media is a paper filter andsaid valve element is imperforate and normally closes said opening insaid adapter.
 11. The device as set forth in claim 7 together with atubular discharge member joined to the inner circumference of saidannular shoulder and extending through said annular filter mEdia to theadjacent end of said cartridge.
 12. The device as set forth in claim 11wherein said filter media is a depth type filter and said valve elementis a secondary filter media.
 13. The device set forth in claim 6 whereinthe center portion of said leaf spring adapter is formed with acylindrical wall extending axially inwardly into said central dischargeopening and a transverse bottom wall at the inner end of saidcylindrical wall through which said bypass opening extends.
 14. In afluid filter device, the combination of a housing having a closed endand an open end, a closure plate closing the open end of the housing andprovided with a fluid inlet and a fluid outlet, a filter cartridgepositioned in the housing and including an annular filter media having acentral discharge passage extending longitudinally through the annularfilter media and communicating with said fluid outlet, support means onsaid closure plate for the adjacent end of said cartridge, a one pieceleaf spring adapter interposed between the other end of the cartridgeand said closed end of the housing for biasing the cartridge againstsaid support means, said adapter having a central opening communicatingwith said discharge passage in said filter media, said cartridge alsoincluding an annular end cap covering said annular filter media andengaged by said leaf spring adapter, an inner circumferential wallextending inwardly from said end cap concentrically with said dischargepassage, and an annular shoulder on said circumferential wall ininwardly spaced relation from said end cap, together with a compressionspring within said circumferential wall seated on said annular shoulder,and a valve element interposed between said spring and said adapter,said valve element normally covering said opening in the adapter butbeing deflectable from the adapter against the action of said spring touncover the opening as a function of excessive fluid pressuredifferential at the outside of the cartridge and the inside of saiddischarge passage.
 15. The device as set forth in claim 14 which isfurther characterized in that said valve element is imperforate andnormally closes said opening in the adapter.
 16. The device as set forthin claim 14 which is further characterized in that said valve elementcomprises a screen covering said opening in the adapter, said screenconstituting a secondary filtering media additional to the annularfilter media of said cartridge.
 17. The device as set forth in claim 14wherein said adapter has a substantially circular center portionprovided with said opening, said center portion of the adapter beingseated within said inner circumferential wall of said cartridge.
 18. Thedevice as set forth in claim 14 wherein said inner circumferential wallof said cartridge is longitudinally coextensive with said filter mediaand defines said discharge passage, said annular shoulder being providedintermediate the ends of said circumferential wall adjacent said endcap.
 19. The device set forth in claim 18 wherein said annular shoulderis a flattened annular bead formed integrally with said innercircumferential wall.
 20. The device as set forth in claim 14 whereinsaid end cap and said inner circumferential wall and said annularshoulder are of one-piece construction.
 21. The device as set forth inclaim 14 wherein said inner circumferential wall and said annularshoulder are of one-piece construction but separate from said end cap,said circumferential wall having an outer endprovided with an out-turnedflange which is interposed between the end cap and said adapter.
 22. Thedevice as set forth in claim 14 wherein a portion at least of theannular end cap is substantially flat and the leaf spring adapterincludes end portions engaging the interior of the closed end of thehousing and flat intermediate portions engaging the flat annular portionof said end cap over a substantial area.
 23. In a fluid filter device,the combination of a housing havinG a closed end and an open end, aclosure plate closing the open end of the housing and provided with afluid inlet and a fluid outlet, a filter cartridge positioned in thehousing and including an annular filter media having a central dischargeopening extending longitudinally through the annular filter media andcommunicating with said fluid outlet, support means on said closureplate for the adjacent end of said cartridge, a spring adapterinterposed between the other end of said cartridge and said closed endof the housing for biasing the cartridge against said support means,said adapter having a center portion closing said central dischargeopening at one end and having a bypass opening communicating with saidcentral discharge opening and resilient means extending from said centerportion and bearing against the inner surface of said closed end of saidhousing, said filter cartridge having first imperforate tubular portionfitting snugly within said central discharge opening and having anannular shoulder spaced inwardly from said other end of said cartridgeand from said adapter, said valve adapter also including a tubularportion fitting snugly within said first imperforate tubular portion andremovable therefrom, a valve element comprising a screen interposedbetween said annular shoulder and said adapter and normally coveringsaid bypass opening, and coil spring means interposed between saidannular shoulder and said valve element for biasing said valve elementagainst said adapter, said spring means being deflectable from saidadapter to permit said valve element to uncover said central opening insaid adapter as a function of excessive fluid pressure differential atthe outside of the cartridge and the inside of said central discharge,and said screen serving as a secondary filter.
 24. The fluid filterdevice as set forth in claim 23 wherein a perforated tubular dischargemember extends from said annular shoulder through said annular filtermedia to the end of the cartridge adjacent to the closure plate.